For many years, green plants have been considered beneficial to their environment, in that they take up carbon dioxide and give off oxygen, and activated carbon has long been known to adsorb onto its extensive surface a wide variety of contaminants in gaseous form.
Combination of such desirable capabilities has been suggested, as by B. C. Wolverton of NASA in Nat'l Space Technology Laboratories papers; a notable example is "Houseplants, Indoor Air Pollutants, and Allergenic Reactions" (MS 39529, dated December 1986). Other persons have reported Wolverton's views and have advanced their own, including Joan Gandy, "Nature's Way" in Garden Club of America's GCA Bulletin, Aug. 15, 1986, pp. 14-18; and (anon.) "Indoor Pollution Solution" in Rodale's Practical Homeowner, September 1986, p. 18. Yet it has remained for the present inventor to modify such teachings so as to achieve practical success in such purification, as below.